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- 2017
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:2
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Ackermann, Kathrin, et al.
(författare)
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N-2 Fixation in Feather Mosses is a Sensitive Indicator of N Deposition in Boreal Forests
- 2012
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Ingår i: Ecosystems. - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 15:6, s. 986-998
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen (N) fixation in the feather moss-cyanobacteria association represents a major N source in boreal forests which experience low levels of N deposition; however, little is known about the effects of anthropogenic N inputs on the rate of fixation of atmospheric N-2 in mosses and the succeeding effects on soil nutrient concentrations and microbial community composition. We collected soil samples and moss shoots of Pleurozium schreberi at six distances along busy and remote roads in northern Sweden to assess the influence of road-derived N inputs on N-2 fixation in moss, soil nutrient concentrations and microbial communities. Soil nutrients were similar between busy and remote roads; N-2 fixation was higher in mosses along the remote roads than along the busy roads and increased with increasing distance from busy roads up to rates of N-2 fixation similar to remote roads. Throughfall N was higher in sites adjacent to the busy roads but showed no distance effect. Soil microbial phospholipid fatty acid (PLFA) composition exhibited a weak pattern regarding road type. Concentrations of bacterial and total PLFAs decreased with increasing distance from busy roads, whereas fungal PLFAs showed no distance effect. Our results show that N-2 fixation in feather mosses is highly affected by N deposition, here derived from roads in northern Sweden. Moreover, as other measured factors showed only weak differences between the road types, atmospheric N-2 fixation in feather mosses represents a highly sensitive indicator for increased N loads to natural systems.
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| 3. |
- Ackermann, Thomas, et al.
(författare)
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An overview of wind energy-status 2002
- 2002
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Ingår i: Renewable & sustainable energy reviews. - 1364-0321 .- 1879-0690. ; 6:1-2, s. 67-128
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Forskningsöversikt (refereegranskat)
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| 4. |
- Ackermann, Thomas, et al.
(författare)
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Distributed generation : a definition
- 2001
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Ingår i: Electric power systems research. - 0378-7796 .- 1873-2046. ; 57:3, s. 195-204
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Tidskriftsartikel (refereegranskat)
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| 5. |
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| 6. |
- Ackermann, Thomas
(författare)
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Distributed Resources in a Re-Regulated Market Environment
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis analyses the value that distributed resources(DR) can contribute to an economically effcient operation of are-regulated electricity market and discusses the relevantchanges in the regulatory framework to allow the appropriatedevelopment of DR whenever DR may increase the economiceffciency of the electricity market. Distributed resources thereby combine two aspects:Distributed generation and demand-side resources. Distributedgeneration is defined as generation within the distributionsystem or on the customer side of the meter. Demand-sideresources are those load resources on the customer-side thatcan be used to shift electricity demand from peak to off-peakperiods, or to reduce the overall electricity demand. To gain a better understanding of the value that DR mayprovide in a re-regulated market, an analysis of there-regulation approaches in England andWales, Scandinavia,Australia, New Zealand as well as in two regions in the USA isperformed. The key findings of this analysis are that non ofthe re-regulation approaches put special emphasis on DR. Thecomparison also shows that despite very different approachesused in the various markets, the remaining re-regulationproblems are very similar. These key problems are mainlyrelated to market power in the various markets and littlecompetition in network services. The thesis shows that DR has the potential to improveoverall economic market effciency by reducing market powerissues and increasing competition in network services. Forinstance, many DR business schemes have no incentive toexercise market power, because withholding generation may havea negative impact on the complex revenue stream from differentincome sources. While this may not allow the general conclusionthat DR will always provide benefits to market operation, it isimportant to consider that not all DR need to provide suchbenefits, as it was also shown that already comparatively smallamounts of demand resources or distributed generation cansignificantlyreduce market power issues. In addition, it wasalso shown that DR can introduce competition into networkservices and therefore can provide incentives for distributionand transmission network companies to operate more costeffectively. It was also demonstrated that the potential of DR to improveoverall economic market effciency will only be realized if: 1. DR is developed in the correct size, i.e. DR should fitinto an existing distribution network and may increase networkutilization rate,2. DR is developed at the correct location in thenetwork, e.g. in areas with congestion problems,3. DR is in operation during the correct times, whenbeneficial to the market, e.g. during times when market powerissues may arise, and4. independent ownership of DR projects isencouraged. Market regulations therefore must provide the correctincentives for the correct siting and operation of DR as wellas for independent ownership. The thesis uses examples andempirical data to explain the relevant regulatory aspects indetail and provides suggestions for a regulatory framework thatconsiders the potential of DR to improve overall economiceffciency in an electricity market.
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| 7. |
- Ackermann, Thomas, et al.
(författare)
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Economic Aspects of Wind Power in Power Systems
- 2005
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Ingår i: Wind Power in Power Systems. - Chichester, UK : John Wiley & Sons. - 9780470855089 ; , s. 383-410
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Ackermann, Thomas, et al.
(författare)
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Electricity market regulations and their impact on distributed generation
- 2000
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Ingår i: Electric Utility Deregulation and Restructuring and Power Technologies, 2000. Proceedings. DRPT 2000. International Conference on. - 078035902X ; , s. 608-613
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Konferensbidrag (refereegranskat)abstract
- Distributed generation (DG) has attracted a lot of attention recently and might become more important in future power generation systems. As different definitions are used worldwide, the paper briefly discusses the definition of DG. The future development of DG, however, will, to a not insignificant part, depend on the legal framework. As the legal framework can vary significantly for different competitive electricity markets, this paper briefly identifies and analyses some variations in the regulatory approaches, e.g. for power exchanges, balance services and ancillary services, in different countries. It also illustrates the influence of market regulations on the development of distributed power generation. Based on this analysis, it can be concluded that regulatory aspects might decisively influence the development of distributed power generation
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