Intermittency Of Renewables?… Not So Much

[kristopher]

3. Right, variable renewables are not a significant technical hurdle

The National Academy of Sciences concluded that we'll need to enact policies that favor renewable integration to enable a penetration into the 50% range, and that above that, we'd need to restructure the nature of the grid so that it is centered around the generating characteristics of renewables instead of centralized generator. In sum these changes mean a computerized "smart grid" that can watch power flow down to the single kilowatt level and the bolstering of technologies that can ramp up and down quickly - specially designed turbine generators (that can run off of either natural gas or biomethane) and various forms of storage fit this need.

See also:
Cost-minimized combinations of wind power, solar power and electrochemical storage, powering the grid up to 99.9% of the time
Open Access Article

Abstract
We model many combinations of renewable electricity sources (inland wind, offshore wind, and photovoltaics) with electrochemical storage (batteries and fuel cells), incorporated into a large grid system (72 GW).

The purpose is twofold:

1) although a single renewable generator at one site produces intermittent power, we seek combinations of diverse renewables at diverse sites, with storage, that are not intermittent and satisfy need a given fraction of hours. And
2) we seek minimal cost, calculating true cost of electricity without subsidies and with inclusion of external costs.

Our model evaluated over 28 billion combinations of renewables and storage, each tested over 35,040 h (four years) of load and weather data.

We find that the least cost solutions yield seemingly-excessive generation capacity — at times, almost three times the electricity needed to meet electrical load. This is because diverse renewable generation and the excess capacity together meet electric load with less storage, lowering total system cost.

At 2030 technology costs and with excess electricity displacing natural gas, we find that the electric system can be powered 90%–99.9% of hours entirely on renewable electricity, at costs comparable to today's—but only if we optimize the mix of generation and storage technologies.

Full article available http://www.sciencedirect.com/science/article/pii/S0378775312014759