Bill Gross 分享新能源的发现之旅

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http://dotsub.com/view/684bba0c-39eb-415b-833a-c94e4b274949
Bill Gross 分享新能源的发现之旅
我从15岁开始对太阳能产生兴趣 我家那时候搬离Fort Lee， 从New Jersey 到 California， 生活环境也从寒冷变为酷热， 到处可见燃气管道。 1973年燃气紧缺，实行配额供给。 能源危机令人厌烦。
我开始阅读大众科学杂志， 了解到太阳能能解决能源危机， 这让我十分的幸奋。 我在高中学习了三角学 了解了抛物线的知识 知道抛物线可以将光线聚集到一点， 这又使我兴奋不已。 我明确地感觉到， 有很大的可能性 去做出一种东西， 一种能够将光线汇聚集中起来设备。
接下来， 我建了个公司，名叫太阳能设备。 在公司里， 我制作抛物线型的太阳能收集器， 我走进进五金行 清楚记得我走进五金行， 制作太阳能收集器和斯特灵机 用车床做斯特灵机 所有的街头小子过来围观 说， 你在做抽大麻的，是不？ 我回答说，“不， 是斯特灵机，斯特灵机。“ 可是他们不信我说的。
我卖了斯特灵机和太阳能收集器的设计图纸 在流行科学杂志的后面，售价4美元 这个收入足够支付我在加州理工的第一年的学费 能够进入加州理工使我激动不已
加州理工的第一年， 我仍继续着我的买卖。 但是接下来的第二年， 校方开始实行分数制。 第一学年，成绩只有过于挂， 但是第二年开始对成绩评分了。 这使我不能继续我的生意了， 这一终止，就是25年的跨度。 我那时的理想是在一个可实行的价格上转换太阳能， 但是却面临了这个巨大的改道。 首先， 在加州的课业。
然后，当我毕业时，IBM个人电脑出现出现了 于是在1981年我开始对个人电脑着迷了。 接下来的1983， Lotus1-2-3出现， 我又彻底的转向Lotus1-2-3. 开始为1-2-3写插件， 做起了1-2-3的生意， 为1-2-3写了自然语言的界面 当我加入Lotus之后，还创办了一家教育软件公司 接着着手于建立创思实验室， 创思实验室提供了一个平台， 可以让我连续的设立多个公司
然后，很久很久以后--2000， 及时最近， California 面临了新的能源危机 早就预见的能源危机，到来了 我一直尝试寻找是否存在一些方法 令我们可以建立某种可以投资的 可以使人们重新回到能源议题的东西， 以备能源危机确实来到 我开始朝如何做备用电池的方向寻找方法 这种备用电池应该能保证5小时，10小时，甚至是一整天， 或是三天的供电。
很高兴今天早些时候， 你们已经了解到电池是很不靠谱的能源， --与燃料相比电池的能量密度实在太小。 也就是说燃料中储存的能量远大于电池中储存的。 需要一个车库的停车空闲 去满足仅仅4个小时的电池储备。 在研究了其它技术后，我认为 我们可以这样储存能量-- 飞轮， 与电池不同的飞轮-- 也许储存电力并非一个具操作性的方法
那么如何产生能量？ 或许我们能够产生能量。 我尝试想出办法--太阳能或许就是这个办法 这距离我上次想使用太阳能已经25年了， 让我回顾先太阳能芯片发生了怎样的变化。 价格已经由1瓦10美金降到1瓦4或5美金， 然后就不再下降了。 我们知道这个价格还是需要下降才能有足够的吸引力。
我学了关于太阳能芯片的所有新进展 尝试寻找革新的突破口 使太阳能芯片更加便宜。 过去几年的确发生了许多新发展， 但是归根结底， 制造芯片的过程本身需要大量的能量。 有些人会说制造太阳能芯片的能量 比我们能在芯片寿命其间得到得能量要多。 从乐观的角度来想， 如果我们能够降低生产过程所需能量， 那么太阳能利用将更加的可行。 但是就如今而言， 大家还是要使用硅， 将硅至于华氏1600度环境中长达17小时， 才能制作此芯片。 大量的人从事这项研究以期降低能耗， 但是就我而言， 在这个研究方向没什么可以开展的。 所以我就想从别的什么方向着手， 以期使太阳能更加经济地产生电力
所以我想到了用反射器来收集太阳能 就像我曾经在高中时想的一样-- 不同的是， 借助现代科技，我们或许可以做更便宜，更大的收集器 聚集太阳能与一个小的电能转换器， 并且电能转换器不会那么的贵， 这是因为它与太阳能芯片相比更小， 太阳能芯片是要将覆盖其整个表面的阳光转换为电。 如今看起来可行性大大提高了， 过去25年产生的大量新科技促使了这点。
首先， 大量的新的制造技术， 例如，小型电动机-- 无刷马达，伺服机，多级电机， 这些主要是应用于打印机，扫描仪或是其他类似的东西。 恩， 这些都是技术上的突破。 当然还有较便宜的微处理器 和非常重要的突破性技术，那就是基因算法。
我接下来会简单地介绍基因算法。 基因算法是一种非常有效地利用自然选择原理来解决棘手问题的方法。 当你遇到不能用纯数学的方法来解决的问题， 可以建立一个类似进化的系统， 通过猜测可能的解来进行求解的过程， 你设立繁殖过程-- 在这个过程中，用各自两个可能解的一半来繁殖产生新的可能解-- 然后用自然选择的原理来舍弃不好的肯能解。 通常来说， 如今在3G的处理器计算机上 用基因算法 你可以解决很多常规无法解决的问题 这个求解过程仅仅需要几分钟的时间。 我们已经用这个基因算法来进行 制造新型太阳能收集器的尝试。 接下来我将展示我们的成果。
常规来讲，太阳能收集器看起来是这个样子的。 抛物线形状。 抛物线形状能够将照射在其表面的平行光汇聚到一点。 为了一直实现这个， 抛物线体必须随着太阳而动。 通常只能接受一度的偏差。 也就是说， 如果超过这一度的偏差， 将不会有一丝光线能够聚集到焦点上。 所以呢，我们有必要想出个方法，可以让太阳能收集器不必随着太阳而转动， 却能接受更大的偏差，增强汇光能力， 保持太阳能收集器不转。 所以我们尝试用基因算法解决这个， 做了个多表面的反射器， 令人惊讶的结果产生了， 经过一兆次的循环， 即一兆次的尝试， 通过一个适应性函数用以决定我们能收集多少光能， 从太阳而来的，一整天的，不同的角度的光线。
这就是那个模型。 不需跟着太阳跑的，具有6个类似角状物的太阳能收集器， 每个角以以下方式收集太阳能-- 如果光线角度正好， 光线将直接反射到焦点， 但是如果光线偏离轴线，从侧边而来， 那么光线将照射角状物两次，即反射两次。 总结下，如果光线角度正好，只反射一次， 如果光线偏离轴线，那么将要反射两次， 对极度偏离轴线的光线，将需要3次反射。 效率随反射次数的增加而减少， 每次反射将损失10%的能量。 好处是，光线角度的接受范围扩大了正负25度。 所以呢， 一天中有一个半小时的时间，我们完全可以用固定不动的太阳能收集器来接受太阳能。
然而太阳能光电池一天可以收集四个半小时的光能。 平均来讲-- 由于太阳的天空轨迹， 太阳能光电池的性能是个正弦曲线函数 随角度而改变。 平均一天四个半小时的收集能力， 没有移动部件是个非常优秀的性能-- 我们虽然能达到较高的温度，但是持续的时间不够长。 需要击败太阳能光电池的这一优点， 恩， 我们现在看看另外一个想法。
于是我们尝试将一个抛物线整体分解成多个独立的瓣 于是有了这个12瓣体， 每个瓣由独立的微处理器控制， 现在微处理器1美元就可以买到 一个两兆的，1美元 还可以买到几乎不会磨损的步进电机 步进电机由于没有刷，所以不太会有报废的可能。 50美金就可以控制这12个瓣体 于是呢，我们就不用再移动焦点了， 只需改变瓣体的位置。 整个系统变得不那么引人注意， 但是我们却能利用它在一天里收集6个半小时，甚至是7个小时。
我们目前解决了汇聚光线的问题， 那么如何进一步使这些光能转换成电能？ 我们尝试过检视历史上的不同引擎 实现光能向电能的转换，即热能想电能的转换。 一直以来最优秀的其中一个， Jame Watt 的1788年蒸汽机是其中主要的突破。 实际上， James Watt 并没有发明蒸汽机， 他只是改进蒸汽机。 但是，他的改进是非比寻常的。 增加了活塞的直线运动， 增加了冷凝器用以冷凝缸体外的蒸汽， 他制作了双动引擎，从而可以产生两倍的功。 这些主要的技术突破。 我是说， 所有这些他引进的改良-- 另能量以他的名字为单位。 所以我们将目光投向蒸汽机，基于其可能性。 蒸汽机是危险地， 众所周知，蒸汽机对世界产生了巨大影响-- 工业革命，船只，汽车。 通常来说，大体积没有问题， 有利于分布产生的能量。 由于高压，蒸汽机具有危险性。
另一种是热空气引擎。 同样地，热空气引擎也不是Rober Stirling 发明的， 但是他在1816年全面改进了这种引擎。 这种引擎只能用空气驱动，而不是用蒸汽， 由于这一有趣的特性，多年来衍生了很多创造性的设计 基于斯特灵机原理。
斯特灵机之后，Otto 产生了， 同样地，并不是Otto发明了内燃机， 他改进了内燃机。 1867年巴黎，Otto 展示了内燃机， 这是重大的成就 因为内燃机是引擎的能量密度提高了。 现在可以在相对小的空间里获得更多的能量 这个技术使引擎能够移动。 所以，你可以自由组合， 现在能够用大量的引擎组合单元， 蒸汽船或是大的工厂里却不能够使用如此多的单元， 内燃机利于量产化 而其他各类引擎都不具备此能力。 所以，因为大量的内燃机生产出来， 成本降下来，在100年间的改进中， 排放降低，这些都意义非凡。 数亿的内燃机呗生产出来， 而斯特灵机却只能以千记。 蒸汽机更是少之又少， 除了应用于大的场合的大型蒸汽机。 当检视完这三种引擎， 还有47种其他的， 我们得出结论，斯特灵机最适宜。
我将简要介绍它如何工作以及我们如何利用它。 接下来我们试图用新的视角来利用斯特停机， 由于它的实用性--轻巧的重量适于我们的应用 内燃机过于笨重，因此不适用， 毕竟有移动的需求。 但是当尝试在一个固定的位置利用太阳能 重量问题就不重要了。 另外一个不需要考虑的是效率， 当能量来源是免费可得时。 通常情况下， 效率是必须考虑的。 因为相对于燃料费用， 初期购买费用实在是不那么多。 但是在燃料是免费供应的时候， 唯一影响投资的就是引擎的价格了。 所以你不会急于优化效率， 重要的是优化投资与产出。 接下来用这个新的标准来 重新检视斯特灵机， 同时将基因算法引进。
基本来讲，Rober Stirling 时代还没出现 Gordon Moore 也就没有3兆处理器的辅助。 再次用之前用过的基因算法 来设计之前不太管用的太阳能收集器 从而优化斯特灵机。 完成设计尺寸 最优的设计就是能够使每一美元可以产生最多的能量， 无须考虑重量与尺寸， 因为太阳能是免费的，所以重点就是尽可能多转换太阳能加以利用。
我们就是以这个为出发点来设计的-请让我向你展示引擎是如何工作的。 最简单的热机，或是热空气机， 由钢铁的缸体和活塞组成。 燃烧使活塞向上运动。 停止燃烧用水冷去，活塞就做向下运动。 这就是热机。 大家能得到的最基本的热机。 问题在于效率只有百分之一。 因为热量是用于加热整个缸体的金属体， 相应地每次也需冷却整个缸体的金属体。 可是每次地，你只利用了被加热的空气的能量， 于是也就浪费了所有用来加热和冷却金属的那部分能量 接着有人很清楚地意识到， 不需对整个缸体进行加热和冷却， 不如在缸体里充入替代物-- 使空气来回的运动。 用少量的能量来移动它 但是能够做到将空气下移到热端，上移到冷端， 再下移到热端，上移到冷端。 于是，现在你不是交替加热与冷却金属， 而是交替加热和冷却空气。 这种做法能够让效率从百分之一提高到 大约百分之二。
这个聪明的设想是有Robert Stirling 提出的， 不加热金属部分了现在， 但是在这种引擎里，我还得从新加热所有的空气。 仍旧是每次循环里，完全加热空气，然后再完全的冷却它。 如果我在中间置一热储存体呢， 就在空气每次必须通过的冷热端之间的通道里？ 他做了个网，和打碎的玻璃， 还有其他不同的材料，用来做那个热储存体。 当空气由热端流向冷端，抬高活塞 将一部分的热储存在热储存体中。 当空气从冷端流回热端时， 已经是冷的了 将先前储存的热利用起来。 你就能够重复使用你的能量5-6次。 将效率提高到30-40个百分比。 这项Rober Stirling 的发明很少被人知道，但却非常的聪明地 将热空气机从不实用-- 就如我在高中时所认为的那样-- 变为非常地有潜力， 一旦你可以以较低的投入设计出这种引擎，那么效率就会提高了。
我们确实在如何降低成本上下了很多功夫 我们开发了一个很大的数学模型用来解决斯特灵机工作的问题。 通过基因算法 取得了一些结果。 在过去的两年里做了百余种不同的引擎。 测试每一个，调整模型， 得出了现在的这个原型。 非常紧凑，并且不贵。 这就是这个引擎的外形。 让我想你展示它。 恩， 这就是我们的引擎。 这下面有个小的缸体， 里面是所有的零件和发生器 这里是热端--顶部的热的活塞== 这个部分变热，这个部分温度较低， 可以输出电能。 相反的转换也可实现。 如果输入电能，这将变热，这儿将变冷， 你可以当冷却装置用。 所以是个可逆循环， 非常的有效率，并且制作容易。
恩现在你能将两样东西放在一块儿。 现在有了引擎， 如果你将瓣体和引擎放在一起。 瓣体将追逐阳光，引擎获得被聚焦了的阳光， 利用其热能，转换为电能。 这个是我们的第一个原型的样子 在中间有板梯和引擎。 在阳光中运行。 现在我想展示下原型。 （掌声） 谢谢。
具有12个瓣体。 每个板梯大概1美金-- 轻质的，吹塑塑料，表面镀铝。 每个瓣体下有个微型处理器来控制它。 在引擎下有测温计--小的传感器 用以观测照其表面的太阳光能量。 每个瓣体独立调整以保证最大限度的温升。 早晨太阳升起时， 瓣体将搜寻太阳位置， 通过感应最高的温度 一两分钟后，光线将聚焦在热端 引擎开始足够热，能够开始工作了 一天大概能产电6或者6个半小时-- 太阳扫过天空的6或者6个半小时。
我们利用的很好的一个重要的部件是 这些便宜的微处理器 使每个瓣体能够独立调整， 找寻太阳的位置，无需人工干预。 所以你不用告诉纬度海拔等信息， 也不用告诉你屋顶的角度， 处在何地。 那些都不需要考虑。 它会自动搜寻最热点， 半小时后再搜寻一次，每天后再搜寻一次， 每月后再搜寻一次。 基本上可以通过太阳移动的方式告诉你，你身在何处。 所以你不许输入任何东西。
这个单元工作的方式是，当太阳升起 引擎开始工作，你开始获得能源 交流或者直流电， 12伏特的直流， 可用于一定的地方。 还有个转换器， 所以也能得到117伏特的交流电 也能得到热水， 热水产出是可选的。 如果你不用热水，没关系，自己会冷却的。 但是你可以选择使用这热水， 这将是效率进一步提高， 因为不用的话就损失那一部分， 可以用在游泳池或是热水。
让我展示下工作时的样子。 这是第一次在外的演示， 看到每个瓣体独立搜寻。 逐步的搜寻，先是比较粗糙地， 接着较精细地搜寻。 一旦热传感器上的温度显示已经找到了太阳， 速度就降下来，开始微调， 每个瓣体各就各位，引擎开始工作。
我们在这上面画了过去两年的时间。 对进展非常的兴奋， 也有很大的进步空间， 再补充说下， 这是可用于住户的设备， 你肯能有多个在房顶。 可以再房顶，后院，或是别的什么地方。 不是要你安装很多，来全权的为你的房子供电， 只是通过安装这个可以省些钱。 你可以通过安装这个设备， 来作为储备能源--当然，晚上不能用， 阴天不能用。
在用电高峰时段，可以减低你的能源需求-- 通常是开空调，或是其他什么时候-- 在高峰时段里为你产能， 所以这个意义上非常的能起到辅助作用。 这是我们开发民用设备的过程。
我们认为有很大潜力来开发一个能源农场 特别是在边缘地区，通常有很充沛的阳光。 这是非常有利的两个组合因素。 研究表明显然地，世界上有大量的太阳能， 在一些特殊的地方，恰巧放置这些太阳能设备又代价很低， 同样的是风能的情况。
这里举个例子， 美国的地图。 只要不是绿色和蓝色的地方都是非常理想的地方， 即使是那些绿色和蓝色的地方也是不错的， 只是没有红，橘和黄色地段的那样好。 在拉斯维加斯和死亡谷周围的热点， 是特别，特别的适宜。
这个是影响回报周期， 但是并不意味着你不能用太阳能， 你可以在世界上任何一个地方使用太阳能。 只是回报周期不同， 与从商业电网买电相比。 但是当你没有电网时， 回报问题又是另外一个了， 只是每美元你能得到多少度电， 和你是如何受益于太阳能 改变你的生活。
美国地图， 世界地图 你能看见巨大的一带在中部 那里有着众多的人口， 极大的太阳能使用机会。 当然，看看非洲地区。 你无法想象那里的太阳能潜力， 关于帮助方式的发现，我是很乐意去谈的。
恩， 总的来说， 我的经历可以告诉你， 用新的角度方法来重新发展旧的想法， 那些在过去可能不现实的主意， 在今天可能会很有实用价值， 因为我们有新的科技或新的进展的辅助。 相信我们已经离实用性和可负担的设计非常的近了。 短期目标是价格为太阳能电池的一半。 长期目标是是短于5年的投资回报。 如果5年内能够取得回报，所有的一切将变得非常的经济。
你将不只基于关心能源问题 而想购置这么一个设备。 从经济上来说，太阳能源也将变得是非常明智的选择 现在，回报周期在30-50年。 如果这个周期短于5年，那么根本不用考虑了， 由于其益处--会有人资助你的 所以说，从第一天开始你就是赚的 所以那时我们公司的终极目标。
从中我学道德两件其他的事情是 第一件，我们对于能源是多么的习以为常， 从电梯走到这， 甚至看看现在的讲台- 大概有20500瓦的照明灯， 有10000瓦的灯照向讲台， 1马力是756瓦特， 全力的。 所以基本上是有15匹马全力的跑动带动了讲台的照明。 跟别提带该有200匹马现在在跑 以维持空调运行。 非常令人讶异，走进电梯，电梯里有灯照明。
当然了，现在我对家里不必要的开灯非常敏感。 但是， 我们周遭到处有无止尽的能源需求， 原因是价格如此的低。 便宜是因为我们接受了 有太阳汇聚积累下的能量。 本质来讲，石油也是太阳能的聚集。 是10亿年来的太阳能 使之凝聚在石油之中。 我们不明智的只是尽快地使用这些能量。 我认为，使能量循环利用，是非常重要的， 将我们使用的能量与产生的能量保持平衡， 我真心希望可以实现这一点。
非常感谢，谢谢您的听讲。
（掌声）♫
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Bill Gross shares great ideas for finding new energy
Right when I was 15 was when I first got interested in solar energy. My family had moved from Fort Lee, New Jersey to California, and we moved from the snow to lots of heat, and gas lines. There was gas rationing in 1973. The energy crisis was in full bore.

I started reading Popular Science magazine, and I got really excited about the potential of solar energy to try and solve that crisis. I had just taken trigonometry in high school, I learned about the parabola and how it could concentrate rays of light to a single focus. That got me very excited. And I really felt that there would be potential to build some kind of thing that could concentrate light.

So, I started this company called Solar Devices. And this was a company where I built parabolas, I took metal shop, and I remember walking into metal shop building parabolas and Stirling engines. And I was building this Stirling engine over on the lathe, and all the biker guys -- motorcycle guys -- came over and said, "You're building a bong, aren't you?" And I said, "No, it's a Stirling engine. It really is." But they didn't believe me.

I sold the plans for this engine and for this dish in the back of Popular Science magazine, for four dollars each. And I earned enough money to pay for my first year of Caltech It was a really big excitement for me to get into Caltech.

And my first year at Caltech, I continued the business. But then, in the second year of Caltech, they started grading. The whole first year was pass/fail, but the second year was graded. I wasn't able to keep up with the business, and I ended up with a 25-year detour. My dream had been to convert solar energy at a very practical cost, but then I had this big detour. First, the coursework at Caltech.

Then, when I graduated from Caltech, the IBM PC came out, and I got addicted to the IBM PC in 1981. And then in 1983, Lotus 1-2-3 came out, and I was completely blown away by Lotus 1-2-3. I began operating my business with 1-2-3, began writing add-ins for 1-2-3, wrote a natural language interface to 1-2-3. I started an educational software company after I joined Lotus And then I started Idealab, so I could have a roof under which I could build multiple companies in succession

Then, much much later -- in 2000, very recently, the new California energy crisis -- or what was purported to be a big energy crisis -- was coming. And I was trying to figure if there was some way we could build something that would capitalize on that and try and get people back-up energy, in case the crisis really came. And I started looking at how we could build battery back-up systems that could give people five hours, 10 hours, maybe even a full day, or three days worth of back-up power.

I'm glad you heard earlier today, batteries are unbelievably energy -- lack of density compared to fuel. So much more energy can be stored with fuel than with batteries. You'd have to fill your entire parking space of one garage space just to give yourself four hours of battery back-up. And I concluded, after researching every other technology that we could deploy for storing energy -- flywheels, different formulations of batteries -- it just wasn't practical to store energy.

So what about making energy? Maybe we could make energy. I tried to figure out -- maybe solar's become attractive. It's been 25 years since I was doing this, let me go back and look at what's been happening with solar cells. And the price had gone down from 10 dollars a watt to about four or five dollars a watt, but it stabilized. And it really needed to get much lower than that to be cost effective.

I studied all the new things that had happened in solar cells and was trying to look for ways we could innovate and make solar cells more inexpensively. There are a lot of new things that are happening to do that, but fundamentally the process requires a tremendous amount of energy. Some people even say it takes more energy to make a solar cell than it will give out in its entire life. Hopefully, if we can reduce the amount of energy it takes to make the cells, that will become more practical. But right now, you pretty much have to take silicon, put it in an oven at 1600 degrees Fahrenheit for 17 hours, to make the cells. A lot of people are working on things to try and reduce that, but I didn't have anything to contribute in that area. So I tried to figure out what other way could we try and make cost-effective solar electricity.

So I thought of an idea -- what if we collect the sun with a large reflector -- like I had been thinking about way back when, when I was in high school -- but maybe with modern technology we could make a cheaper, large collector concentrate it to a small converter, and then the conversion device wouldn't have to be as expensive, because it's much smaller, rather than solar cells, which have to covering the entire surface area that you want to gather sun from. This seemed practical now, because a lot of new technologies had come in the 25 years since I had last looked at it.

First of all, there was a lot of new manufacturing techniques, not to mention, really cheap miniature motors -- brushless motors, servo motors, stepper motors, that are used in printers and scanners and things like that. So, that's a breakthrough. Of course, inexpensive microprocessors and then a very important breakthrough -- genetic algorithms.

I'll be very short on genetic algorithms. It's a powerful way of solving intractable problems using natural selection. You take a problem that you can't solve with a pure mathematical answer, you build an evolutionary system to try multiple tries at guessing, you add sex -- where you take half of one solution and half of another and then make new mutations -- and you use natural selection to kill off not as good solutions. Usually, with a genetic algorithm on a computer today, with a three gigahertz processor you can solve many, many formerly intractable problems in just a matter of minutes. We tried to come up with a way to use genetic algorithms to create a new type of concentrator. And I'll show you what we came up with.

Traditionally, concentrators look like this. Those shapes are parabolas. They take all the parallel incoming rays and focus it to a single spot. They have to track the sun, because they have to be pointing directly at the sun. They usually have about a one degree acceptance angle, meaning once they're more than about a degree off, none of the sunlight rays will hit the focus. So we tried to to come up with a way of making a non-tracking collector, a collector that would gather much more than one degree of light, with no moving parts. So we created this genetic algorithm to try this out, we made a model in XL of a multi-surface reflector, and an amazing thing evolved, literally evolved, from trying a billion cycles, a billion different attempts, with a fitness function that defined how can you collect the most light, from the most angles, over a day, from the sun.

And this is the shape that evolved. It's this non-tracking collector with these six tuba-like horns, and each of them collect light in the following way -- if the sunlight strikes right here, it might bounce right to the center, the hot spot, directly, but if the sun is off-axis and comes from the side, it might hit two places and take two bounces. So for direct light, it takes only one bounce, for off-axis light it might take two, and for extreme off-axis, it might take three. Your efficiency goes down with more bounces, because you lose about 10 percent with each bounce. but this allowed us to collect light from a plus or minus 25 degree angle. So, about two and a half hours of the day we could collect with a stationary component.

Solar cells collect light for four and a half hours though. On an average adjusted day, a solar cell -- because the sun's moving across the sky, the solar cell is going down with a sine wave function of performance at the off-axis angles. It collects about four an a half average hours of sunlight a day. So, even this, although it was great with no moving parts -- we could achieve high temperatures -- wasn't enough. We needed to beat solar cells. So we took a look at another idea.

We looked at a way to break up a parabola into individual petals that would track. So what you see here is 12 separate petals, that each could be controlled with individual microprocessors that would only cost a dollar. You can buy a two megahertz microprocessor for a dollar now. And you can buy stepper motors that pretty much never wear out because they have no brushes, for a dollar. We can control all 12 of these petals for under 50 dollars and what this would allows us to do is not have to move the focus any more, but only move the petals. The whole system would have a much lower profile, but also we could gather sunlight for six and a half to seven hours a day.

Now that we have concentrated sunlight, what are we going to put at the center to convert sunlight to electricity? So we tried to look at all the different heat engines that have been used in history to try and convert sunlight to electricity, or heat to electricity. And one of the great ones of all time, James Watt's steam engine of 1788 was a major, major breakthrough. James Watt didn't actually invent the steam engine, he just refined it. But, his refinements were incredible. He added new linear motion guides to the pistons, he added a condenser to cool the steam outside the cylinder, he made the engine double-acting so it had double the power. Those were major breakthroughs. I mean, all of the improvements he made -- and it's justifiable that our measure of energy, the watt, today is named after him. So we looked at this engine, and this had some potential. Steam engines are dangerous, and they had tremendous impact on the world, as you know -- industrial revolution and ships and locomotives. But they're usually good to be large, so they're not good for distributed power generation. But they're also very high pressure, so they're dangerous.

Another type of engine is the hot air engine. And the hot air engine also was not invented by Robert Stirling, but Robert Stirling came along in 1816 and radically improved it. This engine because -- it was so interesting, it only worked on air, no steam, has led to hundreds of creative designs over the years that use the Stirling engine principle.

But after the Stirling engine, Otto came along, and also, he didn't invent the internal combustion engine, he just refined it. He showed it in Paris in 1867, and it was a major achievement because it brought the power density of the engine way up. You could now get a lot more power in a lot smaller space and that allowed the engine to be used for mobile applications. So, once you have mobility, now you're making a lot of engines because you've got lots of units, as opposed to steam ships or big factories where you're not making as many units, so this was the engine that ended up benefiting from mass production where all the other engines didn't benefit. So, because it went into mass production, costs were reduced, 100 years of refinement, emissions were reduced, tremendous production value. There have been hundreds of millions of internal combustion engines built, compared to thousands of Stirling engines built. And not nearly as many small steam engines being built anymore, only large ones for big operations. So after looking at these three, and 47 others, we concluded that the Stirling engine would be the best one to use.

I want to give you a brief explanation of how we looked at it and how it works. So we tried to look at the Stirling engine in a new way, because it was practical -- weight no longer mattered for our application The internal combustion engine took off because weight mattered because you were moving around. But if you're trying to generate solar energy in a static place the weight doesn't matter so much. The other thing we discovered is that efficiency doesn't matter so much if your energy source is free. Normally, efficiency is crucial because the fuel cost of your engine over its life dwarfs the cost of the engine. But if your fuel source is free, then the only thing that matters is the up-front capital cost of the engine. So you don't want to optimize for efficiency, you want to optimize for power per dollar. So using that new twist, with the new criteria, we thought we could re-look at the Stirling engine, and also bring genetic algorithms in.

Basically, Robert Stirling didn't have Gordon Moore before him to get us three gigahertz of processor power. So we took the same genetic algorithm that we used earlier to make that concentrator, which didn't work out for us, to optimize the Stirling engine. and make its design sizes and all of its dimensions the exact optimum to get the most power per dollar, irrespective of weight, irrespective of size, to get the most conversion of solar energy, because the sun is free.

And that's the process we took -- let me show you how the engine works. The simplest heat engine, or hot air engine, of all time would be this -- take a box, a steel canister, with a piston. Put a flame under it, the piston moves up. Take it off the flame and pour water on it, or let it cool down, the piston moves down. That's a heat engine. That's basically the most fundamental heat engine you could possibly have. The problem is the efficiency is one hundredth of one percent. because you're heating all the metal of the chamber and then cooling all the metal of the chamber each time. And you're only getting power from the air that's heating at the same time, but you're wasting all the energy heating the metal and cooling the metal So someone came up with a very clever idea, to -- instead of heating the whole cylinder and cooling the whole cylinder, what about if you put a displacer inside -- a little thing that shuttles the air back and forth. You move that up and down with a little bit of energy but now you're only shifting the air down to the hot end and up to the cold end, down to the hot end and up to the cold end. So, now you're not alternately heating and cooling the metal, you're just alternately heating and cooling the air. That allows you to get the efficiency up from a hundredth of a percent to about two percent.

And then Robert Stirling came along with this genius idea, which was, well I'm still not heating the metal now, with this kind of engine, but I'm still reheating all the air. I'm still heating the air every time and cooling the air every time. What about if I put a thermal sponge in the middle, in the passageway between where the air has to move between hot and cold? So he made fine wires, and cracked glass, and all different kinds of materials to be a heat sponge. So when the air pushes up to go from the hot end to the cold end it puts some heat into the sponge. And then when the air comes back after it's been cooled it picks up that heat again. So you're reusing your energy five or six times. and that brings the efficiency up between 30 and 40 percent It's a little known, but brilliant, genius invention of Robert Stirling that takes the hot air engine from being somewhat impractical -- like I found out when I made the real simple version in high school -- to very potentially possible, once you get the efficiency up, if you can design this to be low enough cost.

So we really set out on a path to try and make the lowest cost possible We built a huge mathematical model of how a Stirling engine works. We applied the genetic algorithm. We got the results from that for the optimal engine. We built engines -- so we built 100 different engines over the last two years. We measured each one, we readjusted the model to what we measured, and then we led that to the current prototype. It led to a very compact, inexpensive engine And this is what the engine looks like. Let me show you what it looks like in real life. So this is the engine. It's just a small cylinder down here which holds the generator inside and all the linkage and it's the hot cap -- the hot cylinder on the top -- this part gets hot, this part is cool, and electricity comes out. The exact converse is also true. If you put electricity in, this will get hot and this will get cold, you get refrigeration. So it's a complete reversible cycle, a very efficient cycle, and quite a simple thing to make.

So now you put the two things together. So you have the engine, now what if you combine the petals and the engine in the center. The petals track and the engine gets the concentrated sunlight, take that heat and turn it into electricity. This is what the first prototype of our system looked like together with the petals and the engine in the center. This is being run out in the sun, and now I want to show you what the actual thing looks like. (Applause) Thank you.

So this is a unit with the 12 petals These petals cost about a dollar each -- lightweight, injection bolted plastic, aluminized The mechanism to control each petal is below there with a microprocessor on each one There are thermocouples on the engine -- little sensors that detect the heat when the sunlight strikes them. Each petal adjusts itself separately to keep the highest temperature on it. When the sun comes out in the morning, the petals will seek the sun, find it by searching for the highest temperature About a minute and a half, or two minutes, after the rays are striking the hot cap the engine will be warm enough to start and then the engine will generate electricity for about six and a half hours a day -- six and a half to seven hours as the sun moves across the sky

A critical part that we can take advantage of is that we have these inexpensive microprocessors and each one of these petals are autonomous, and each one of these petals figures out where the sun is with no user set-up. So you don't have to tell what latitude, longitude you're at, you don't have to tell what your roof slope angle is, you don't have to tell what orientation. It doesn't really care. What it does is it searches to find the hottest spot, it searches again a half an hour later, it searches again a day later, it searches again a month later It basically figures out where on Earth you are by watching the direction the sun moves so you don't have to actually enter anything about that.

The way the unit works is, when the sun comes out the engine will start and you get power out here We have AC and DC, get 12 volts DC, so that could be used for certain applications. We have an inverter in there, so you get 117 volts AC and you also get hot water. The hot water's optional. You don't have to use the hot water, it will cool itself. But you can use it to optionally heat hot water and that brings the efficiency up even higher because some of the heat that you would normally be rejecting, you can now use as useful energy, whether it's for a pool or hot water.

Let me show you a quick movie of what this looks like, running. So this is the first test where we took it outside and each of the petals were individually seeking. And what they do is step, very coarsely at first, and then very finely, afterward. Once they get a temperature reading on the thermocouple indicating they found the sun, then they slow down and do a fine search, then all the petals will move into position, and then the engine will start.

So, we've been working on this for the last two years. We're very excited about the progress, we do have a very long way to go though still, and let me tell you a little bit more about that. This is how we envision it would be in a residential installation you'd probably have more than one unit on your roof. It could be on your roof, or in your backyard, or somewhere else You don't have to have enough units to power your entire house, you just save money with each incremental one you add. So you're still using the grid potentially, in this type of application, to be your back-up supply -- of course, you can't use these at night, and you can't use these on cloudy days.

But by reducing your energy use, pretty much at the peak times -- usually when you have you air conditioning on, or other times like that -- this generates the peak power at the peak usage time, so it's very complementary in that sense. This is how we would envision a residential application.

We also think there's very big potential for energy farms especially in remote land where there happens to be a lot of sun. It's a really good combination of those two factors. It turns out there's a lot of powerful sun all around the world, obviously, but in special places where it happens to be relatively inexpensive to place these and also in many more places where there is high wind power.

So an example of that is, here's the map of the United States Pretty much everywhere that's not green or blue is a really ideal place, but even the green or blue areas are good, just not as good as the places that are red, orange and yellow. But the hot sport right around Las Vegas and Death Valley and that area is very, very good.

And all this does is affect the payback period, it doesn't mean that you couldn't use solar energy, you could use solar energy anywhere on Earth. It just affects the payback period if you're comparing to grid-supplied electricity. But if you don't have grid-supplied electricity, then the whole question of payback is a different one entirely. It's just how many watts do you get per dollar, and how could you benefit from that using that power to change your life in some way.

This is the map of the United States. This is the map of the whole Earth and again, you can see a huge swathe in the middle of pretty much where a large part of the population is, there's tremendous chances for solar energy. And of course, look at Africa. It's just unbelievable what the potential is to take advantage of solar energy there, and I'm really excited to talk more about finding ways we can help with that.

So, in conclusion, I would say my journey has shown me that you can revisit old ideas in a new light, and sometimes ideas that have been discarded in the past can be practical now if you apply some new technology or new twists. We believe we're getting very close to something practical and affordable. Our short-term goal for this is to be half the price of solar cells and our longer-term goal is to be less than a five-year payback And at less than a five-year payback, all of a sudden this becomes very economic

So you don't have to just want to have a feel-good attitude about energy to want to have one of these. It just makes economic sense. Right now, solar paybacks are between 30 and 50 years. If you get it down below five years then it becomes almost a no-brainer because the interest to own it -- someone else will finance it for you and you can just make money, basically from day one. So that's our real powerful goal that we're really shooting for in the company.

Two other things that I learned that were very surprising to me -- one was how casual we are about energy. I was walking from the elevator over here, and even just looking at the stage right now -- so there's probably 20 500 watt lights right now. There's 10,000 watts of light pouring on the stage, one horsepower is 756 watts, at full power. So there's basically 15 horses running at full speed just to keep the stage lit. Not to mention the 200 horses that are probably running right now to keep the airconditioning going. And it's just amazing, walk in the elevator and there's lights on in the elevator.

Of course now, I'm very sensitive at home when we leave the lights on by mistake. But, everywhere around us we have insatiable use for energy because it's so cheap. And it's cheap because we've been subsidized by energy that's been concentrated by the sun. Basically, oil is solar energy concentrate. It's been pounded for a billion years with a lot of energy to make it have all that energy contained in it. And we don't have a birthright to just use that up as fast as we are, I think. And it would be great if we could find a way to make our energy usage renewable, where as we're using the energy we're creating it at the same pace, and I really hope we can get there.

Thank you very much, you've been a great audience.
(Applause)