IEEE Power & Energy Magazine - July/August 2016 - 52

that high deployment of very low-cost DeRs does
not eliminate the need for additional transmission
capacity; in fact it increases slightly in a few regions under the distributed PV scenario to optimize
remaining baseload resources.
a more detailed assessment is provided by the January 2015 report, "Impacts of Demand-side Resources
on electric Transmission Planning" by the oak Ridge
national laboratory. The report reviews the results of a
set of studies that belong to the QeR library and were conducted between 2010 and 2013 by electricity regulators,
industry representatives, and other stakeholders in the
three physical interconnections within the united states,
with the objective of determining if demand resources
such as energy efficiency (ee), demand response (DR),
and distributed generation (Dg) have an impact on electricity transmission requirements. The report identifies
five drivers for transmission expansion and discusses the
impacts of demand resources on them. Detailed quantitative results can be found in the report.
✔ Interconnection: Reduced demand generally lowers
the need for new generation and consequent connections to the grid. however, connections to provide
backup or voltage support may still be required, but
these will be largely on the distribution system rather
than transmission.
✔ Reliability: Reduced demands lower the needed
amount of reserves. In addition, DR can serve to provide reserves, thereby freeing existing generation and
transmission assets to provide power.
✔ Economics: Demand resources are at or near loads
and so avoid the cost of distant generation, transmission, and losses. on the other hand, lower demand near
low-cost generation may increase the use of transmission as that power seeks more distant markets.
✔ Replacement: By lowering demand, ee and DR may
lengthen the life span of T&D equipment. however,
utilities may need to upgrade equipment early for Dg
implementation, and smart grid systems that enable demand resources may make older equipment obsolete.
✔ Environmental: Demand resources can provide environmentally attractive alternatives to transmission
plus distant generation. Portfolio standards may recognize these resources for meeting clean energy standards. local clean generation may need to transmit
further distances if local demand is reduced.
The report concludes that the study of the interactions
between demand resources and transmission is in its early
stages, since the models have only begun to incorporate
demand resources realistically as variables in the evaluations, and more has to be done to better understand the
relationship. Planners and modelers are beginning to take
these factors into account, creating co-optimizing models
and better representations of demand resources. Increases
in computing power and funding of other studies will
july/august 2016

further help to advance the science in integrated electricity planning.

Acknowledgments
a group of researchers at the Massachusetts Institute of
Technology in the united states, and at the Institute for
Research in Technology at comillas university in Madrid,
under my supervision, have been thinking hard about these
issues and others, in relation with the future provision of
electricity services, during the last couple of years, sponsored by a large group of firms and institutions (see https://
mitei.mit.edu/research/utility-future-study). This article
borrows ideas from many of the members of this group, in
particular (and in alphabetic order) carlos Batlle, Michael
Birk, scott Burger, José Pablo chaves, Tomás gómez, sam
huntington, Jesse Jenkins, ash Kumar, Max luke, and
Richard Tabors.

For Further Reading
florence school of Regulation. (2013). from distribution
networks to smart distribution systems: Rethinking the regulation of european electricity Dsos. [online]. available:
http://www.eui.eu/Projects/ThInK/home.aspx
european climate foundation. (2011). Power perspectives 2030. [online]. available: http://europeanclimate.org/
power-perspectives/
european climate foundation. (2010). Roadmap 2050.
[online]. available: http://www.roadmap2050.eu/project/
roadmap-2050
h. Wirth, "Recent facts about photovoltaics in germany,"
fraunhofer Institute for solar energy systems Ise, germany, Dec. 2015.
International energy agency (Iea). (2016). Repowering markets. [online]. available: https://www.iea.org/
publications/freepublications/publication/RePoWeRIngMaRKeTs.pdf
u.s. Department of energy. (2015). Quadrennial energy Review. [online]. available: http://energy.gov/epsa/qer-documentlibrary
u.s. oak Ridge national laboratory. (2015, Jan.). Impacts of demand-side resources on electric transmission
planning. [online]. available: http://energy.gov/sites/
prod/files/2015/01/f19/Impact_DsR_on_Transmission_
PlanningV6_0.pdf
I. J. Pérez-arriaga, s. Ruester, s. schwenen, c. Batlle,
and J.-M. glachant. (2013). from distribution networks to
smart distribution systems: Rethinking the regulation of european electricity Dsos. [online]. available: http://cadmus.
eui.eu/handle/1814/27615

Biography
Ignacio J. Pérez-Arriaga is with the Massachusetts Institute of Technology, Boston, and comillas university,
Madrid, spain.
p&e

ieee power & energy magazine

http://https:// http://mitei.mit.edu/research/utility-future-study http://www.eui.eu/Projects/ThInK/home.aspx http://www.europeanclimate.org/ http://www.roadmap2050.eu/project/ https://www.iea.org/ http://www.energy.gov/epsa/qer http://www.energy.gov/sites/ http://cadmus http://www.eui.eu/handle/1814/27615

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - July/August 2016