Thomas G. Bourgeois, deputy director of Pace University’s Energy and Climate Center, provided this response for the Dot Earth blog when asked, after the Hurricane Sandy disaster, how distributed generation of electricity and heat could cut disaster impacts and mesh with efforts to develop renewable energy sources in cities.
Related Dot Earth post: http://nyti.ms/U5blIP
Pace Energy and Climate Center:
A Systems Approach to Resilient and Sustainable Urban Energy Supply
Thomas G. Bourgeois, deputy director of Pace University’s Energy and Climate Center,provided this response for the Dot Earth blog when asked, after the Hurricane Sandydisaster, how distributed generation of electricity and heat could cut disaster impactsand mesh with efforts to develop renewable energy sources in cities.Gas fired district systems or Microgrids with CHP [combined heat and power] are anally, not foe, of renewables. The multi-building, district model utilizes the gas far moreefficiently and can create an eco-system of various energy resources all optimized tocreate greater value than possible in single site.When you lay the electric conduit and thermal pipes you are “future proofing” yourenergy system. This is essential infrastructure for more cost effectively delivering allforms of energy, including and especially renewable energy. The pipes and wires are notspecific to the form of generation – whereas you may be using gas combustion turbinesor reciprocating engines now, in the near to intermediate term these same pathways cancarry renewable generated power and thermal energy. (District Energy St. Paul is a casein point – also, see the Danish experience in this regard)When power is generated, the waste heat is simultaneously utilized in a productivemanner to provide hot water, space heating and cooling, process heat or steam,sterilization, drying, a variety of economic services. That can come from renewables aswell as gas.Enlarging the vision from “zero energy building” to “zero energy neighborhoods”represents a quantum leap in the potential opportunity set. At the individual buildinglevel you are limited by the quirks of that building and by the very specific types ofeconomic activities taking place within it. When you diversify your opportunity set toseveral proximate buildings you typically can achieve far more. You can take advantageof complementary electric and thermal load profiles. For example, I recall a project sitein New England that I visited a few years ago. On one side of the street was a facility thathad a large demand for thermal energy (steam and hot water) and very modest demandfor heat. If they sized a CHP system to meet internal thermal needs, it would have been ~10 MW’s --- but – internal demand was just 2 MW’s. On the other side of the street wasa facility that had a tremendous demand for power and small thermal demand. Theyneeded 14 MWs of power. Sizing the CHP system to meet thermal needs would haveresulted in satisfying just 25 – 30% of electric demand.In each building, CHP was a marginal or poor investment – but – joining the two, was aspectacular efficiency win for both.If you have, say, a dozen buildings, some will have good PV [solar panel] exposure,others not so good. Some can be easily retrofitted for Energy efficiency improvements,others not so easy. Space may be available at one parcel, not at another.MGrids and District systems with CHP could create a portfolio of resources; PV, solarthermal, other clean DG, combine it with gas fired CHP, and energy efficiency retrofits,demand response. The entire system is controlled with algorithms that optimize when touse the PV internally and when to export it to maximize returns. When to use the DR,
when to turn up/down the CHP (gas) system.The gas CHP is dispatchable and can be turned up/down readily for load following(particularly recip engines). This is a nice balancing feature for the intermittentrenewables. Renewables (PV, small wind) do not possess all the attributes of an idealgeneration source. Power output can fluctuate quickly, causing problems for systemstability (requiring frequency and voltage support). The intermittents can be augmentedby battery and energy storage – a lot of good analysis on this in CA --- but that ispresently costly.PV, CHP, storage, DR, EE can all work together as a new energy eco-system where thevalue of the sum of the parts is far superior to each individually.To fully exploit the value proposition we do need a smarter grid. We need better twoway communications between the microgrid and macrogrid. To fully take advantage ofRE and DG as a dynamic asset on the grid, requires communications and control flowingtwo ways – not the one way design we have now.There are problems working alongside existing network protection schemes, but theengineering problems are solvable.One concern I have been expressing is regarding our distribution system investments.$100’s of millions are spent annually. These are very long-lived assets with service livesof 30+ years. Investments we make today will be in service in 2045 (or do we pay“STRANDED DISTRIBUTION COSTS” to utilities?)As we make new investment in the distribution system what is being done to insure thata. the system is becoming more amenable to higher DG penetration over time, in synchwith stated goals, ANDb. that we encourage the DG to be a dynamic asset on the system, one that can play apositive role, rather than an added cost to the system... is anyone piloting markets for DG services on the distribution system? For statesencouraging much higher penetration of DG as matter of policy, shouldnt we examinehow the DG and the distribution system ought to be configured to permit these newresources to act as "good citizens" in ability to offer grid services?I sent the brief below to NYSERDA last summer.…………………………………..Distribution System InvestmentsNew York State has set aggressive goals for an 80% reduction in carbon emissions by2050. In addition, New York has set a target of attaining 30% of state energyrequirements through renewable energy sources by 2015.These shorter and longer term goals and objectives will require fundamental changes to
the current electric transmission and distribution system. The existing T&D system wasnot designed for and is not particularly amenable to marked increases in the penetrationlevels of distributed generation. Therefore, alongside goals for renewable energy, highefficiency DG and deep carbon reductions, by implication and of necessity there ought tobe a similar requirement for T&D system goals that will enable this result and capturethe full value of these anticipated distributed energy resources.New York’s distribution utilities are investing daily in the existing distribution system.Capital investments made by utilities often have very long service lives. In someinstances investments made today have regulatory asset lives that continue up to andbeyond the year 2040 . It is imperative that long-lived investments be screened toinsure that they are in synch with announced state and local policies (e.g. New YorkCity’s PlaNYC) goals to increase the state’s reliance on distributed generation and energygenerated from renewable sources.In the 21st century to what extent are the investments we make replacing the ageddistribution system with a 21st century capable system, or to what extent simply with areplace parts-in-kind, type of system?Do current protocols for assessing the prudence of new T&D capital spending includemetrics for assessing the extent to which the distribution system progressing inaccommodating higher penetration levels of DG? If we fail to take adequate account ofnew grid capital spending in the context of announced public policy we are at risk ofincurring much higher than necessary future grid modernization costs and incurringsignificant distribution stranded investment.Suppose a distribution utility has a choice between capital investment A and B.Investment A and B perform the same services for the system as it is currently configuredand utilized. Investment A costs less than investment B. However, despite its increasedcost, investment B augments the distribution system’s performance with respect to DG onthe network which it serves. Is there any consideration of the net value of investment Bpertaining to anticipated future uses of the distribution system? On the contrary, is there apenalty assessed investment A for risks associated with pre-mature obsolescence? IRS Publication 946, Table B-2, Table of Class Lives and Recovery Periods (2010) IRS Publication 946, Table B-2, Table of Class Lives and Recovery Periods (2010)