05 January 2009

Returning Solar Energy To The Grid

Listening to the 29-Oct-2008 entry from NPR's Technology Podcast, where they're talking about residents and businesses who're going for 'energy zero' (or some term like that, I don't remember it exactly) construction: building homes and buildings with modern materials, solar panels, etc. such that their net draw on utilities is essentially zero. One of the points they bring up is how the reimbursement for excess energy generated and returned to the grid (i.e., the energy use of the home/building is "negative") is paltry compared to the cost of 'positive' energy use, matched per kilowatt-hour, or whatever. The rep they talk to from the utility company (or regulatory body or whatever) brings up some of the various breaks they give to people who build green, and talks about how challenging it is to deal well with customers returning their excess energy to the grid.

Firstly, I'm not sure I really follow why it's all that hard. My brother is currently working in a chemical plant where they often generate excess electricity from their on-site generators, and they have an agreement worked out with the utility company where they return their excess generation to the grid, no problem. (Sure, I expect it's more complex than I realize... still, the capability is there.) What's to stop them from broadening this?

Well. Technologically, perhaps nothing... but from both a logistical sense and a market-share sense, no utility company worth its salt would willingly choose to outsource (essentially) its generation to its customers as things sit right now. On the one hand, if this 'networked' power generation from many thousands of individuals were as robust as the Internet has been for data transfer, then maybe there wouldn't be any logistical problems at all. Buuuut... think of the lawsuits that could be brought! Barring legislative changes (I assume, anyways), the utility company would be liable for the actions of its customers, should those actions result in interruption in the supply of electricity (especially in emergency or critical situations). I can't imagine any power company willingly going along with that!

Further, (loosely) in terms of market share, if a critical mass of customers shifted to 'energy-zero', the utility company would be left to maintain all of its power transmission infrastructure... but with severely curtailed revenues! The current billing approach (at least, on my bill) for electricity is to scale both generation and distribution costs by the amount of electricity consumed. So, if I use 200 kWh one month and 300 kWh the next, both the generation and distribution costs on my bill will be half again as large in that second month (assuming no change in their per-unit costs). But, if I convert my house to 'energy-zero' prior to that third month... I could use that same 200 kWh as the first month on the cloudy days, but return 205 kWh to the grid on the sunny days. Boom presto, based on the current usage-indexed billing system, if I got one-for-one credit for electricity returned to the grid, I would get a refund on that extra 5 kWh... but the grid bore the burden of 405 kWh for my total 'positive' and 'negative' usage!

Rejigger billing so that distribution costs are charged both on energy usage and energy return, and restructure laws & regulations to give the utility companies some protections in an environment where customers will morph into customer-suppliers, and I think we'll have a start toward a much more logical and sustainable power grid. Politics aside, thinking green can really make sense... it just has to be done... well, sensibly.

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