Forum Earth has entered or soon will enter the sixth mass extinction of multicellular life (Wilson 1992(Wilson , 2002. Human activities are the primary reason. Many lines of evidence point toward this involvement, but here we consider a direct one. Our harnessing of energy sources other than our own has provided us with the means not only for creating modern civilization but also for taking a huge fraction of life's annual energy budget provided by plant photosynthesis. Vitousek and colleagues (1986) made the first detailed estimates of how much humans use, directly and indirectly, of the planetary energy budget: 27 percent of global net primary production (NPP) and 39 percent of terrestrial net primary production (tNPP). The flow of commercial energy, and the related confiscation of NPP, has an unavoidable negative effect on biodiversity. The loss of biodiversity in turn raises serious questions about the possibility of creating a durable global civilization.Perspective on the importance of energy flow is gained by comparing current energy flow with the prehistoric flow of energy through hunter-gatherer societies. When this is done, the current mass extinction appears as a predictable, expected result. Such a consequence provides sufficient justification for revising energy policies to reduce the amount and change the type of energy flow.

We analyze the operating-energy histories of three homes of different ages that have approached or attained net-use of no fossil fuels and climate neutrality. The first house (H-60) with 1,200 ft2 is a conventional 1950s house that has been caulked, insulated and equipped with an airtight woodstove and a 3.3 kW photovoltaic system that reduced its annual use of fossil fuels by 86%. Its total annual energy use excluding any passive gain is ∼57 billion joules. House two (H-30) with 2,300 ft2 is a 1980s, passive-solar house with a recently added 4.0 kW photovoltaic system that reduced its annual use of fossil fuels by 71%. Its total annual energy use excluding any passive gain is ∼58 billion joules. House three (H-1) with 1,300 ft2 is a 1 year old, passive solar house with a 3.1 kW photovoltaic system and an evacuated-tube solar hot water system that uses no fossil fuels, exports annually ∼900 kWh to the grid making it energy and climate positive, and provides all operating energy from on-site sunshine. Its total annual energy use excluding any passive gain is ∼29 billion joules.

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While solar photovoltaic (PV) panels have been used successfully to produce electricity for quite some time, it has been technically difficult to capture their heat because of the large area of a flat-plate photovoltaic panel. Likewise it has been difficult to manufacture solar concentrator systems that are of the same physical scale, about one square meter, as successful commercial flat-plate photovoltaic panels and incorporate them into a commercializable and easily manufactured solar energy system. This paper addresses the two problems by considering the feasibility of a single design of a one square meter plastic nonimaging solar concentrator that focuses sunlight on a heat-capturing, dense array of high-intensity photovoltaic chips. The individual one square meter modules are designed to be mounted on a 2-axis tracking system which could have a double polar-axis support for energy and cost efficiency. When coupled with an existing electronic control, these three components create a commercial-scale solar electricity device that also provides heat in quantities suitable for heating or cooling. Preliminary contacts with electric utilities and commercial/industrial businesses have found interest in procurement of the proposed technology for widespread harvesting and use of solar energy in the US and abroad.

Tile purpose of this project was to develop and commercialize a demand defrost controlle, (hat initiates defrosts of refrigeration systems only when required. The standard method of control is a time clock that usually defrosts too often, which wastes energy. The controller developed by this project uses an algorithm based on the temperature difference between the discharge and return of the display case air curtain along with several time settings to defrost only when needed. This controller was field tested in a supermarket where it controlled defrost of the lowtemperature display cases. According to test results the controller could reduce annual energy consumption by 20,000 and 62,000 kWh for hot gas and electric defrost, respectively. The controller saves electJ'ic demand as well as energy, is adaptable to ambient air conditions, and provides valuable savings throughout the year. The savings are greatest for lowtemperature systems that use the most energy. A less tangible benefit of the demand controller is the improvement in food quality that results from fewer defrosts.