Sustainability Journal

September 2012 Issue (files are in PDF format)

Adding solar panels to AE systems.

How to design sustainable communities.

The US Energy Information Administration has issued its annual report on current and future energy consumption in the US.

The projection is for the total energy consumption to reach 112,811 petajoules per year by 2035, of which 73% will be used by residential, commercial and industrial buildings. There is no provision for any of that energy to come from stored thermal energy facilities even though they would be capable of delivering about half of the energy needed by the buildings. The most notable supply change anticipated in the EIA report is in the consumption of natural gas extracted from shale and tight gas formations that require hydraulic fracturing, which over time will release large amounts of methane into the atmosphere. No data is provided in the report on this type of GHG emission.

The EIA report goes to great lengths to consider the market sensitivities to price for fossil fuels but fails to consider the much larger impact of a widespread switch to energy storage that uses clean, renewable energy sources that are free, and it also fails to show how the mandatory need to reduce greenhouse gases to an acceptable level will be met.

2035 US consumption

Residential 23.28 quadrillion Btu

Commercial 21.56 "

Industrial* 33.39 "

(Transportation accounts for 28.75 qBtu)

* Not all of the industries operate indoors but on the other hand many produce large amounts of heat that could be employed if it is stored until needed, plus waste products that can be converted to heat, and many industrial processes require heat so they offer a means of utilizing the stored heat. Matching thermal supply and demand will require innovations but the underlying need is the ability to store the heat.

"Half of the energy needed by buildings" would amount to over 40,000 petajoules. The energy itself is free and the capital cost per kW of capacity is competitive with any of the current alternatives so the challenge for the EIA authors is to explain why their estimates do not take this source into account.

Storing DHW heat

Outlines a proposal for storing heat from a bank of evacuated tube solar collector tubes in the center of an AE heat store. With such a system very little electricity would be needed for the DHW system, it is simpler and less expensive than the alternatives, and the costs of building and operating the AE heat store would be reduced.